Perpendicular view on corners/edges in sculpting mod
if you tab into edit mode, you can use Shift Numpad 7 to look down perpendicular on the active face / selection. This also aligns to edges, but along the edge, not perpendicular to it. Perpendicular alignment is possible with using Shift Numpad 1 when having one edge or two vertices selected. Toggle between Ortho and Perspective using Numpad 5

tab out of Edit Mode again to return to sculpt mode.